How to use StringBuilder, StringBuffer and why you should use them. This video also unveils the mystery of formatting strings with printf() and related methods; vital skills for any Java course or aspiring software developer.

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Code for this tutorial:

publicclassApp{publicstaticvoidmain(String[]args){// InefficientStringinfo="";info+="My name is Bob.";info+=" ";info+="I am a builder.";System.out.println(info);// More efficient.StringBuildersb=newStringBuilder("");sb.append("My name is Sue.");sb.append(" ");sb.append("I am a lion tamer.");System.out.println(sb.toString());// The same as above, but nicer ....StringBuilders=newStringBuilder();s.append("My name is Roger.").append(" ").append("I am a skydiver.");System.out.println(s.toString());///// Formatting //////////////////////////////////// Outputting newlines and tabsSystem.out.print("Here is some text.tThat was a tab.nThat was a newline.");System.out.println(" More text.");// Formatting integers// %-10d means: output an integer in a space ten characters wide,// padding with space and left-aligning (%10d would right-align)System.out.printf("Total cost %-10d; quantity is %dn",5,120);// Demo-ing integer and string formatting control sequencesfor(inti=0;i<20;i++){System.out.printf("%-2d: %sn",i,"here is some text");}// Formatting floating point value// Two decimal place:System.out.printf("Total value: %.2fn",5.6874);// One decimal place, left-aligned in 6-character field:System.out.printf("Total value: %-6.1fn",343.23423);// You can also use the String.format() method if you want to retrieve// a formatted string.Stringformatted=String.format("This is a floating-point value: %.3f",5.12345);System.out.println(formatted);// Use double %% for outputting a % sign.System.out.printf("Giving it %d%% is physically impossible.",100);}}

My name is Bob. I am a builder.
My name is Sue. I am a lion tamer.
My name is Roger. I am a skydiver.
Here is some text. That was a tab.
That was a newline. More text.
Total cost 5 ; quantity is 120
0 : here is some text
1 : here is some text
2 : here is some text
3 : here is some text
4 : here is some text
5 : here is some text
6 : here is some text
7 : here is some text
8 : here is some text
9 : here is some text
10: here is some text
11: here is some text
12: here is some text
13: here is some text
14: here is some text
15: here is some text
16: here is some text
17: here is some text
18: here is some text
19: here is some text
Total value: 5.69
Total value: 343.2
This is a floating-point value: 5.123
Giving it 100% is physically impossible.